The angle of incidence at a solid/liquid boundary is 67.7°, and the index of refraction of the solid is n = 1.75.
(a) What must be the index of refraction of the liquid such that the direction of the light entering the liquid is not changed?
(b) What is the largest index of refraction that the liquid can have, such that none of the light is transmitted into the liquid and all of it is reflected back into the solid?